Method of charging an implantable medical device

• US 20050113889A1
• Filed: 11/29/2004
• Published: 05/26/2005
• Est. Priority Date: 06/16/2000
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Jimenez, Oscar, Kast, John E., Echarri, Guillermo, Riekels, James E., Schommer, Mark E.
• Granted Patent: US 8,170,681 B2
• Time in Patent Office: Days
• US Class Current: 607/61
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

A rechargeable implantable medical device with a magnetic shield placed on the distal side of a secondary recharging coil to improve charging efficiency is disclosed. The rechargeable implantable medical device can be a wide variety of medical devices such as neuro stimulators, drug delivery pumps, pacemakers, defibrillators, diagnostic recorders, cochlear implants. The implantable medical device has a secondary recharging coil carried over a magnetic shield and coupled to electronics and a rechargeable power source carried inside the housing. The electronics are configured to perform a medical therapy. Additionally a method for enhancing electromagnetic coupling during recharging of an implantable medical device is disclosed, and a method for reducing temperature rise during recharging of an implantable medical device is disclosed.

Claims

1. A method of enhancing electromagnetic coupling of an implantable medical device recharging coil, comprising:

positioning a secondary recharging coil in operational relationship to an implantable medical device;

positioning a magnetic shield on a distal side of the secondary recharging coil;

attracting electromagnetic flux lines from a primary recharging coil to the secondary recharging coil with the magnetic shield; and

,

improving electromagnetic coupling between a primary recharging coil and a secondary recharging coil; and

,

improving efficiency of energy transfer from the primary recharging coil to the secondary recharging coil.

2. The method as in claim 1 wherein recharging efficiency is improved through enhanced electromagnetic coupling between the secondary recharging coil and a primary recharging coil.

3. The method as in claim 2 wherein the enhanced electromagnetic coupling is greater than 10 percent coupling efficiency at about one centimeter.

4. The method as in claim 1 wherein the magnetic shield is a material with high magnetic permeability.

5. The method as in claim 4 wherein the magnetic shield is selected from the group consisting of:

amorphous metal film, amorphous metal wire, and magnetic alloy.

6. The method as in claim 1 wherein the secondary recharging coil is carried on the proximal face of the housing and the magnetic shield is placed between the receiving recharging coil and the proximal face of the housing.

7. The method as in claim 1 wherein the secondary recharging coil is an external secondary recharging coil located away from the housing.

8. The method as in claim 1 wherein the medical device is selected from the group consisting of:

neuro stimulators, pacemakers, defibrillators, drug delivery pumps, diagnostic recorders, and cochlear implants.

9. A method of reducing temperature rise during recharging of an implantable medical device external recharging coil, comprising:

positioning a secondary recharging coil in operational relationship to an implantable medical device;

positioning a magnetic shield on a distal side of the secondary recharging coil;

reducing electromagnetic flux lines that couple with the housing;

reducing eddy currents in the housing caused by electromagnetic flux lines that couple with the housing; and

,

reducing temperature rise during recharging because of reduced eddy currents in the housing.

10. The method as in claim 9 wherein recharging efficiency is improved by decreasing flux lines that couple with the housing.

11. The method as in claim 9 wherein recharging efficiency is improved through reduced eddy currents in the housing.

12. The method as in claim 11 wherein reduced eddy currents during recharging also reduces medical device temperature rise during recharging.

13. The method as in claim 9 wherein the temperature rise of the implantable medical device during recharging is less than two degrees Celsius.

14. The method as in claim 9 wherein the magnetic shield is a material with high magnetic permeability.

15. The method as in claim 14 wherein the magnetic shield is selected from the group consisting of:

amorphous metal film, amorphous metal wire, and magnetic alloy.

16. The method as in claim 9 wherein the medical device is selected from the group consisting of:

neuro stimulators, pacemakers, defibrillators, drug delivery pumps, diagnostic recorders, and cochlear implants.

17. A method, comprising the steps of:

operatively coupling a secondary charging coil to an implantable medical device;

positioning a magnetic shield between the secondary charging coil and the implantable medical device; and

coupling electromagnetic flux from the primary charging coil from a side of the secondary charging coil opposite from the magnetic shield.

18. A method of electromagnetic coupling a primary charging coil with a secondary charging coil of an implantable medical device, comprising:

operatively coupling the secondary charging coil to the implantable medical device;

positioning a magnetic shield between the secondary charging coil the implantable medical device; and

electromagnetically coupling the primary coil with the secondary coil from a side of the secondary coil opposite from the magnetic shield.

19. The method as in claim 18 wherein electromagnetic coupling between the primary charging coil and the secondary charging coil is enhanced.

20. The method as in claim 19 wherein the enhanced electromagnetic coupling is greater than 10 percent coupling efficiency at about one centimeter separation between the primary charging coil and the secondary charging coil.

21. The method as in claim 18 wherein efficiency of energy transfer from the primary charging coil to the secondary charging coil is improved.

22. The method as in claim 18 wherein charging efficiency between the primary charging coil and the secondary charging coil is improved.

23. The method as in claim 18 wherein the magnetic shield is a material with high magnetic permeability.

24. The method as in claim 23 further comprising the step of selecting the magnetic shield from the group consisting of:

amorphous metal film, amorphous metal wire, and magnetic alloy.

25. The method as in claim 18 wherein the secondary recharging coil is carried on the proximal face of the housing.

26. The method as in claim 18 wherein the secondary recharging coil is an external secondary recharging coil located away from a housing of the implantable medical device.

27. The method as in claim 18 wherein the medical device is selected from the group consisting of:

neuro stimulators, pacemakers, defibrillators, drug delivery pumps, diagnostic recorders, and cochlear implants.

28. A method of charging of an implantable medical device with an external charging coil, comprising the steps of:

operatively coupling a secondary charging coil to the implantable medical device;

positioning a magnetic shield between the secondary charging coil and the implantable medical device; and

applying electromagnetic flux from the primary charging coil from a side of the secondary charging coil opposite from the magnetic shield.

29. The method as in claim 28 wherein said applying step results in reduced electromagnetic flux lines that couple with a housing of the implantable medical device.

30. The method as in claim 28 wherein said applying step results in reduced eddy currents in the housing of the implantable medical device caused by electromagnetic flux lines that couple with the housing.

31. The method as in claim 28 wherein a temperature rise induced through eddy currents in the housing during charging is reduced.

32. The method as in claim 28 wherein charging efficiency is improved by decreasing flux lines that couple with the housing.

33. The method as in claim 28 wherein charging efficiency is improved through reduced eddy currents in the housing.

34. The method as in claim 28 wherein reduced eddy currents during recharging also reduces medical device temperature rise during charging.

35. The method as in claim 34 wherein the temperature rise of the implantable medical device during charging is less than two degrees Celsius.

36. The method as in claim 28 wherein the magnetic shield is a material with high magnetic permeability.

37. The method as in claim 36 further comprising the step of selecting the magnetic shield from the group consisting of:

amorphous metal film, amorphous metal wire, and magnetic alloy.

38. The method as in claim 28 wherein the medical device is selected from the group consisting of:

neuro stimulators, pacemakers, defibrillators, drug delivery pumps, diagnostic recorders, and cochlear implants.